The CDC states that the “vast majority” of H1N1 cases have been sensitive to Oseltamivir, the generic name for Tamiflu, an antiviral medication that is used against influenza. This implies that there have been Tamiflu-resistant cases known to the CDC. This is in itself not unusual; influenza virus is known to rapidly mutate and when you’re talking about a population of billions in the world, it makes sense that the virus would “try out” some tricks here and there that would lead to drug resistance. Now a few of those cases are showing up clinically and have been in the news over the last two days.

From Reuters:

SYDNEY (Reuters) – The first Australian case of swine flu resistant to Roche Holding AG’s antiviral drug Tamiflu was confirmed by the Western Australia state government on Friday.

“The 38-year-old Perth man, who has a weakened immune system, initially responded to the drug but developed a resistant strain of the virus when his illness relapsed,” the state’s Department of Health said in a statement.

There have been 13 cases of Tamiflu-resistant infections around the world, the statement said.

A Roche executive said on Monday that isolated cases of Tamiflu-resistant H1N1 pandemic flu were to be expected, in line with what has been seen in clinical studies.

“There is no evidence that the virus has spread to other people. None of the patient’s family or hospital staff caring for him have contracted the virus, and he has not been in contact with the wider community,” said the state’s Chief Health Officer Tarun Weeramanthri, adding that the case was a rare and isolated one.

Of more concern in this country has been the story that two campers came down with a drug-resistant variant of the H1N1 virus. The story goes like this: the medical director of the camp decided (against CDC recommendations) to treat everyone at the camp with Tamiflu whether they were at risk or not. It’s no surprise, therefore, that two of the girls developed Tamiflu-resistant virus. What else was the virus supposed to do? If you want to create drug-resistant agents, give everyone in the population the drug and just wait. It’ll happen every time.

The good news is, neither of those girls transmitted the virus to their families (at least according to my sources) and the virus was still sensitive to Relenza, the other antiviral we have at our disposal.

A single person in Australia, 2 campers, and about 10 other cases of Tamiflu resistance should not a panic make.

The CDC recommends that Tamiflu and Relenza be saved to treat only people at risk of serious illness or death from flu — pregnant women, children who seem to have trouble breathing or other serious symptoms, and people with conditions that weaken their immune systems such as diabetes, asthma and heart disease.

I’ll keep you up to date as this thing evolves. For now, WASH YOUR HANDS, stay in if you’re sick until your fever has been gone for at least 24 hours, and if you have to go out, wear a mask or at least cough into your elbow. Remember, Relenza still works, so we’re not faced with Stephen King’s “The Stand” just yet.